Skin Cancer

What Is Skin Cancer?

Skin cancer is the most common type of cancer in the United States, involving abnormal growth of cells in the skin. It can develop when DNA in skin cells is damaged — most often by ultraviolet (UV) radiation from the sun or tanning devices — leading to uncontrolled cell growth. Early detection and treatment are critical, as some forms can grow deeper into the skin and potentially spread to other parts of the body.

Types of Skin Cancer

There are several major types of skin cancer, including:

  • Basal Cell Carcinoma: The most common form, typically slow‑growing and usually treatable when detected early.
  • Squamous Cell Carcinoma: Occurs in the outermost layer of the skin and may appear as a rough, scaly patch or sore that doesn’t heal.
  • Melanoma: A less common but more dangerous form that begins in pigment‑producing cells and is more likely to spread if not treated early.

Causes and Risk Factors

Skin cancer can develop from long‑term exposure to UV radiation, but other factors may increase risk, including:

  • Fair skin that burns easily
  • History of severe sunburns
  • Use of tanning beds
  • Weak immune system
  • Family or personal history of skin cancer

Although risk is higher in those with light skin, people of all skin tones can develop skin cancer.

Signs and Symptoms

Common signs that a lesion may be cancerous include:

  • New growths or spots on the skin
  • Moles or patches that change in size, shape, or color
  • Sores that do not heal
  • Crusty, bleeding, or irregular bumps

Melanoma may follow the “ABCDE” pattern — Asymmetry, Border irregularity, Color variation, Diameter enlargement, and Evolving appearance.

Diagnosis and Treatment

Diagnosis typically begins with a clinical skin exam, followed by a biopsy to confirm whether a lesion is cancerous. Treatment depends on the type, size, and stage of the skin cancer. Common approaches include:

  • Surgical removal: Excisional surgery aims to remove the cancerous tissue and a margin of healthy skin.
  • Mohs surgery: A precise technique to remove skin cancers layer by layer with minimal loss of healthy tissue.
  • Cryotherapy, electrodessication, or topical treatments: For certain superficial lesions.
  • Advanced therapies: Radiation, immunotherapy, or chemotherapy in more aggressive or advanced cases.

Early detection and timely treatment offer the best outcomes and may prevent spread or the need for more extensive therapy.

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Frequently Asked Questions

Skin cancer is the abnormal growth of skin cells, most commonly caused by DNA damage from ultraviolet (UV) radiation, leading to uncontrolled cell division and tumor formation.

Basal cell carcinoma and squamous cell carcinoma are the most common types. Melanoma is less common but more likely to spread.

Diagnosis usually begins with a skin exam and is confirmed with a skin biopsy, where a sample is examined under a microscope.

Signs can include new or changing skin growths, sores that don’t heal, irregular moles, bleeding lesions, or crusty patches.

Many skin cancers are highly treatable, especially when detected early. Surgical removal often cures early basal and squamous cell cancers.

Treatment options range from surgical excision and Mohs surgery to cryotherapy or topical treatments for superficial lesions, and more advanced therapies like radiation or immunotherapy for aggressive cases.